The next-generation mobile communication system (commonly known as 5th-Generation (5G) may further improve quality of services. Besides a conventional requirement on increase of data rate and the like, ensuring continuity of service and meeting quality requirements of different services in multiple environments become important requirements of evolution to a user-centric network. Requirements of services which can be provided by the next-generation mobile communication system are ever-changing, and it is difficult for a single wireless technology to meet all the requirements on the premise of reasonable cost, so that an organic combination of different wireless technologies becomes a more feasible choice.
Under a current technical condition, different Radio Access Technologies (RATs) work without cooperation. When multiple RATs are used for transmission, great defects in performance will occur.